Changing brightness and colors of an image

Question

Here's code for an applet that will create a gradient:
http://www.sitepoint.com/forums/showpost.php?p=1408696&postcount=5
How would you load an image and do this same thing to the image?
Also, how could you add a slider to change the brightness?
Any tips or code samples would be much appreciated.

Answer 1

Here's the code that changes the rgb values. But, it doesn't work in some browsers and earlier versions of jre. Can you fix it so that it works? Also, how would you add to this code to make it change the brightness of an image?
(2 files: grad.java and myPaint.java)
File: grad.java
import java.awt.Color; import java.awt.GradientPaint; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.GridLayout; import java.awt.Rectangle; import javax.swing.JApplet; import javax.swing.JComponent; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JSlider; import javax.swing.SwingConstants; import javax.swing.event.ChangeEvent; import javax.swing.event.ChangeListener; public class grad extends JApplet implements ChangeListener { JSlider[] jss; JPanel mainP, slidP; display disp; Color col1, col2; public void init() { mainP = new JPanel(new GridLayout(1, 2)); slidP = new JPanel(new GridLayout(6, 2)); jss = new JSlider[6]; for (int loop = 0; loop < 6; loop++) { jss[loop] = new JSlider(SwingConstants.HORIZONTAL, 0, 255, 0); jss[loop].addChangeListener(this); } slidP.add(new JLabel("Red 1"), slidP.add(jss[0])); slidP.add(new JLabel("Green 1"), slidP.add(jss[1])); slidP.add(new JLabel("Blue 1"), slidP.add(jss[2])); slidP.add(new JLabel("Red 2"), slidP.add(jss[3])); slidP.add(new JLabel("Green 2"), slidP.add(jss[4])); slidP.add(new JLabel("Blue 2"), slidP.add(jss[5])); //add others in order r1, g1, b1, r2, g2, b2; disp = new display(); mainP.add(disp); mainP.add(slidP); getContentPane().add(mainP); } public void stateChanged(ChangeEvent evt) { col1 = new Color(jss[0].getValue(), jss[1].getValue(), jss[2].getValue()); col2 = new Color(jss[3].getValue(), jss[4].getValue(), jss[5].getValue()); disp.setColors(col1, col2); System.out.println("grad.stateChanged()"); disp.repaint(); } class display extends JComponent { Color col1, col2; public display() { col1 = Color.black; col2 = Color.black; } public void setColors(Color col1, Color col2) { this.col1 = col1; this.col2 = col2; } public void paint(Graphics _g) { Graphics2D g = (Graphics2D) _g; int boxW = 300; int boxY = 300; g.setPaint(new GradientPaint(0, 0, col1, boxW, boxY, col2)); g.fill(new Rectangle(0, 0, boxW, boxY)); } } }
File: myPaint.java
import java.awt.Color; import java.awt.Paint; import java.awt.PaintContext; import java.awt.Rectangle; import java.awt.RenderingHints; import java.awt.geom.AffineTransform; import java.awt.geom.Rectangle2D; import java.awt.image.ColorModel; import java.awt.image.Raster; import java.awt.image.WritableRaster; /* * Created on 16.09.2004 */ public class myPaint extends Object implements Paint { private Color c1, c2; public myPaint(Color c1, Color c2) { this.c1 = c1; this.c2 = c2; } public int getTransparency() { return OPAQUE;//this constant is in Paint class; } public PaintContext createContext(ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform xform, RenderingHints hints) { return new myPaintContext(c1, c2); } class myPaintContext implements PaintContext { private int r1, g1, b1, r2, g2, b2; myPaintContext(Color c1, Color c2) { r1 = (c1.getRGB() >> 16) & 0xff; g1 = (c1.getRGB() >> 8) & 0xff; r1 = c1.getRGB() & 0xff; r2 = (c2.getRGB() >> 16) & 0xff; g2 = (c2.getRGB() >> 8) & 0xff; b2 = c2.getRGB() & 0xff; } public ColorModel getColorModel() { return ColorModel.getRGBdefault(); } public Raster getRaster(int x, int y, int w, int h) { WritableRaster raster = getColorModel().createCompatibleWritableRaster(w, h); int[] data = new int[w * h * 4]; int base = 0; float rat1, rat2; for (int xloop = 0; xloop < w; xloop++) { rat1 = ((float) xloop) / ((float) w);//this is ratio of color1 rat2 = 1 - rat1;//this is ratio of color2; for (int yloop = 0; yloop < h; yloop++) { data[base++] = (int) ((r1 * rat1) + (r2 * rat2)); data[base++] = (int) ((g1 * rat1) + (g2 * rat2)); data[base++] = (int) ((b1 * rat1) + (b2 * rat2)); data[base++] = 255;//alpha } } raster.setPixels(0, 0, w, h, data); return raster; } public void dispose() {} } }